Apparatus to clean an engine without dismantling the engine

ABSTRACT

An internal combustion engine having pistons, cylinders, an air cooler, an air manifold and a turbocharger with a compressor. There is a tank to contain hot water under pressure. The pressure in the tank and the water temperature can be controlled. At least one injector allows heated water to be injected into the turbocharger compressor. A further injector allows water to be injected into the air cooler and a plurality of yet further injectors allow water to be injected into the air manifold. Conduits supply water from the tank to the injectors. Control of flow in the conduits is by valves. The invention permits the cleaning of an internal combustion engine without dismantling the engine or the turbocharger.

FIELD OF THE INVENTION

This invention relates to an apparatus and method for removing depositsfrom an induction system of an internal combustion engine.

DESCRIPTION OF THE PRIOR ART

During the normal operation of internal combustion engines having forcedinduction there is a gradual deterioration in performance. Forcedinduction is usually achieved with a turbocharger, which is a pump toforce air into the engine. Some turbocharger force the fuel/air mixture,but usually only the air is forced. A basic turbocharger comprises aturbine, driven by exhaust gas on a common shaft with a compressor thatincludes a compressor wheel having blades. The compressor wheel isrotated rapidly by the rotation of the turbine and the blades pump theair. One of the main reasons for the deterioration in performance isdeposits on the compressor side of the turbocharger and on the aircooler, air manifold, scavenging ports or exhaust and intake valves.

It is therefore necessary to remove these deposits. At the moment themost common method of removing deposits is to scrape the depositsmanually during scheduled engine overhauls. These overhauls are usuallycarried out after two to five years of operation. This method isexpensive. It requires that the engine and turbocharger be out ofservice and is not, therefore, used frequently. Thus for approximately85 to 95% of operational time engines are working with fouled surfacesof the turbocharger, air coolers, air intake manifolds, scavenging portsor exhaust and intake valves. This fouling significantly increasesexhaust temperature and fuel consumption and decreases air pressure inthe forced induction system.

The air fed into an internal combustion engine contains very fineparticles of dust, moisture, oil and other substances. Various filtersare, of course, used to clean the air but even the best filters cannotcompletely prevent particles from entering the engine. In forcedinduction systems these particles enter the compressor of theturbocharger. Fouling of the engine and of the induction system isinevitable. Intensity of fouling depends on many factors such as thecatching ability of the compressor blades, the quantity of dust and oilin the air and the number of operational hours. It can be shown that themost intensive growth of the deposit layer on the engine componentstakes place during the first fifty to two hundred hours of operation,depending on the engine type and the condition of the operation. In thenext one thousand hours the deposit layer grows slowly and, afterapproximately fifteen hundred to two thousand hours, it stabilizes.

The deposits reduce the passage for air flow, the surfaces becomes roughand the volume of air supplied by the turbocharger into the enginecylinders decreases. As a result, the engine efficiency decreases. Theexhaust temperature and fuel consumption increase and the charged airpressure, and thus available engine power, decrease.

A further disadvantage is that fouling of the turbocharger can causesurge; the deposits reduce the safe margin against the surge line.

To solve these problems, some diesel engine manufacturers have developedsystems for washing turbochargers without dismantling. For example, asystem is known for washing turbochargers in which approximately one totwo liters of cold water is put into a tank and injected into thecompressor through tubing of about 8 to 10 mm diameter. The injection iscarried out by using the pressure of super charged air at 10 to 18pounds per square inch. The washing procedure takes place every 24 to 48hours during normal operation of the engine, without reduction of theengine's revolutions.

This system has not achieved complete success. The deposits are mainlyremoved from the compressor wheel. The compressor's diffuser, wheredeposits settle the most, is hardly affected by this washing system. Asa result, the system is not particularly effective. A furtherdisadvantage is that the deposits removed from the compressor wheel passthrough the air cooler, through the air intake manifold and across theintake valves and the scavenging ports. Unfortunately, because of theway in which the water is introduced, the particles moved from thecompressor settle on these subsequent surfaces. As a result, theimprovements achieved using the above system have been disappointing.

A further approach is to use solvents other than water. This method ismore effective than the use of water but constant use of these solventshas an undesirable effect on the engine oil and also results incorrosion of the pistons, cylinders and other internal parts of theengine. As a result, the use of solvents other than water is not nowused.

There is, therefore, a need for a system able to carry out washing of anengine and turbocharger without dismantling and without simplytransferring deposits from one part of the engine to another.

SUMMARY OF THE INVENTION

Accordingly, and in a first aspect, the present invention is an internalcombustion engine having pistons and cylinders, an air cooler, airmanifold and a turbocharger with a compressor. The internal combustionengine includes a washing system that comprises a tank to contain hotwater, means to apply pressure to the tank, means to control thepressure in the tank, at least one first injector to allow heated waterto be injected into the turbocharger compressor, at least one secondinjector to allow water to be injected into the air cooler, a pluralityof third injectors to allow water to be injected into the air manifold,conduits to supply water from said tank to said first, second and thirdinjectors, and valve means to control water flow in said conduits.

The present invention resulted from a thorough analysis of the problemof deposition on forced induction components. It was found that thedeposits on the compressor of the turbocharger, the air cooler, the airintake manifold and the intake valves are produced by polymerization oflubricating oil, dust, moisture and other substances. First it was thatthe use of hot water is desirable. Furthermore, there is an optimum sizeof water droplets. In general, the size of water droplets depends on theengine power, the type and size of the turbocharger, the size of the aircooler and the diameter and length of the air intake manifold. In apreferred embodiment the optimum size of water droplets for washing thecompressor is obtained by injecting water at 25 to 35 pounds per squareinch through an injector with an opening of about 0.9 to 1.5 mm. For theair cooler, the pressure is the same but the jet that directs wateragainst the air cooler is of a size 1.5 to 2.5 mm. For the air intakemanifold, again the pressure is as indicated above but the injector hasa size in the range 1.5 to 3 mm.

It is further found that the injector for the compressor should bepointed at the base of the blades of the compressor and should belocated about 4 to 10 mm off the center line of the rotor of theturbocharger. The most effective distance between the nozzle tip and thecompressor wheel is about 3 to 6 mm.

The optimum quantity of water required for washing should be determinedbased on the proportion of 0.04 kg per second of water for 1 kg persecond of air used by the engine. Alternatively, 0.6 grams of water foreach square meter of surface to be cleaned may be used.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated, merely by way of example, in the drawingsin which:

FIG. 1 is a graph relating deposit removal to water temperature;

FIG. 2 illustrates the injector installation for a turbocharger'scompressor;

FIG. 3 is a graph relating the amount of water to effectiveness ofdeposit removal; and

FIG. 4 is a diagrammatic view of an engine according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIG. 4, a conventional turbo charged diesel engine isshown. The engine is entirely conventional. It includes pistons andcylinders (not shown), a cylinder head 100, a turbocharger 102 having aturbine 104, a shaft 106 and a compressor wheel 108 that is part of thecompressor. The compressor is not shown in FIG. 4 but is shown partiallyin FIG. 2. The engine includes an air cooler 110 and air manifold 112.

According to the invention the engine is modified to include a tank 3 tocontain hot water. There are means to apply pressure to the tank in theform of a supply of compressed air of 25 to 35 pounds per square inchthrough conduit 2. Conduit 2 is controlled by a valve 14 which thusprovides a means to control the pressure in the tank 3. The tank 3includes means to heat the water in the form of a simple heating coil 4.There is a thermostat 5 to control the water temperature. In a preferredembodiment the thermostat 5 controls the temperature of the water toabout 95° to 96° C.

There is a water supply conduit 1 to the tank 3 controlled by valve 13.The tank also has an air vent 7 and a pressure relief valve 6. Thepressure in the tank 3 should be controlled so that the pressure doesnot exceed double the working pressure of 25 to 35 pounds per squareinch.

There are injectors 9 to allow heated water to be injected into thecompressor. A conduit 12, controlled by valve 17, extends from the tankto the injectors 9. Hot water is also supplied from the tank 3 byconduit 11 to air cooler injectors 19. Conduit 11 is controlled by valve18.

Finally, the air manifold 112 has injectors 29 to receive hot water fromthe conduit 10. Flow in conduit 10 is controlled by valves 15 and 16.

As shown particularly in FIG. 2, the compressor comprises a casing 21with compressor wheel 108 mounted on a shaft 23 and located by nut 24.There is an injector 25 that directs water against the base of thecompressor wheel 22. The water should be directed at about 4 to 10 mmfrom the center line 26 of the shaft 23 and its tip should beapproximately 3 to 6 mm from the adjacent surface of the wheel 108 forbest results.

The system works as follows. The water tank 3 is filled with cold freshwater and heated by means of the heater 4. The thermostat 5 controls theheater 4 and automatically switches off the heater 4 when thetemperatures reaches about 95° to 96° C. Valve 14 on the compressed airline 2 is opened to apply a pressure of 25 to 35 pounds per square inchto tank 3. Valve 17 in conduit 12 is opened and water under the abovepressure is injected through the injector 9, which has a diameter of 0.9to 1.5 mm, into the compressor. The same procedure is repeatedsequentially to inject water into the air cooler 110 and then separatelyinto the air intake manifold 112 by controlling valves 15, 16 and 18 asneeded.

This arrangement of washing the deposits ensures that deposits removedfrom one component do not settle on another. In particular depositsremoved from the compressor do not settle on the air cooler or on thewalls of the air intake manifold. The procedure takes about 5 to 15minutes, depending on the engine power, the number of turbocharger andthe like.

FIG. 1 illustrates that the water temperature should be about 96° C. Atthat temperature approximately 95% of 15 the deposits are removed withwater pressure at 25 pounds per square inch.

FIG. 3 illustrates the amount of water that should be applied. With aspecific water consumption of 0.6 kg per meter square of surface area tobe cleaned there is a removal of deposits greater than 93%.

I claim:
 1. In an internal combustion engine having pistons andcylinders, an air cooler, an air manifold and a turbocharger with acompressor, the improvement that comprises:a tank to contain hot water;means to apply pressure to the tank; means to control the pressure inthe tank; at least one first injector to allow hot water to be injectedinto the compressor; at least one second injector to allow hot water tobe injected into the air cooler; a plurality of third injectors to allowhot water to be injected into the air manifold; conduits to supply hotwater from said tank to said first, second and third injectors; andvalve means to control water flow in said conduits.
 2. An engine asclaimed in claim 1 in which the tank includes means to heat said waterand a thermostat to control said water temperature.
 3. An engine asclaimed in claim 2 in which the thermostat controls the temperature ofthe water to about 95° to 96° C.
 4. An engine as claimed in claim 1including a water supply conduit to said tank;a valve in said conduit tocontrol the water supply.
 5. An engine as claimed in claim 1 in whichthe means to apply pressure to the tank is compressed air;a conduit tosupply said air to said tank from a source; and a valve in said conduitto control supply.
 6. An engine as claimed in claim 5 in which apressure relief valve operates to control air pressure in the tank sothat pressure does not exceed double working pressure.
 7. An engine asclaimed in claim 1 in which said at least one first injector has anopening with a size in the range 0.9 to 1.5 mm.
 8. An engine as claimedin claim 1 in which said turbocharger includes a compressor wheel withblades, said injector directing water at a point close to roots of saidblades.
 9. An engine as claimed in claim 8 in which the water isinjected along a line about 4 to 10 mm from the center line of therotor.
 10. An engine as claimed in claim 9 in which the jet outlet islocated about 3 to 6 mm from the compressor blades.
 11. An engine asclaimed in claim 1 in which the second injector has an opening with asize in the range 1.5 to 2.5 mm.
 12. An engine as claimed in claim 1 inwhich the third injectors each have an opening with a size in the range1.5 to 3 mm.
 13. A method of cleaning a forced induction internalcombustion engine, the engine having a turbocharger that includes acompressor, an air cooler and an air manifold, the method comprisinginjecting hot water separately into said compressor, air cooler and airmanifold.
 14. A method as claimed in claim 13 in which the watertemperature is in the range 95° to 96° C. and the pressure of injectionis about 25 to 35 pounds per square inch.
 15. A method as claimed inclaim 13 in which the hot water is injected at the rate of about 0.04 kgper second of water per 1 kg per second of air used by the engine.
 16. Amethod as claimed in claim 13 in which the hot water is injected at therate of about 0.6 grams per square meter of surface to be cleaned.